I'm going to talk to a leader I haven't met in the afternoon. I don't know where his office is yet. What should I say when texting before I leave?

First, go to the leadership office to see if anyone else is here. If there is, don't send a text message, don't call. And judging from your leadership, he will be sitting in the office of that department. If two people don't know, you can only send a text message to gently explain what you don't understand.